Hydraulic transmission



2 Sheets-Sheet 1 Filed May 24, 1952 Fig.1

Jmgentor:

Era"; J M

Attorney May 7, 1957 E ST R 2,791,184

. HYDRAULIC TRANSMISSION Filed May 24, 1952 2 Sheets-Sheet 2 Jnvenfor" Ems. .rrun M Attorney United States Patent jil his-in vention relates to rotany ,.piston engines, and more l-pafticularly to improvementspf the rot-ary piston engine-described in my Patent No.--.2 ,049,092, of'tluly 28,

19:36, for Rotary piston engine especially ifOl :fluid Rotarypiston eng ines, especially for:fluid rgears, .have acquired 'practical importance only when frictional losses were reduced toa Teasonabledegreeby rotatably mountingthe casing surrounding the vanadium andithe v-anes.

lhe vanes reciprocably arranged in radial ."sl'ots of the it'pisfton drum or rotor are guided by the cylindricaliinner surface of the rotary casingand byihe abutting surfaces arranged centrically"r'lative"to saitlinner surface. Ac-

edrdirr ao lite rotar-y piston engine descii bedinabove mentioned U. S. Patent 2,049,092 the vanes are in abutting engagement with the associated guiding surfaces by means of semi-cylindrical pins. This construction, however, is comparatively expensive and not quite satisfactory as far as quietness of action is concerned.

It is therefore the main object of the invention to provide for a simplified construction of such type of a device as described and shown in my Patent No. 2,049,092, mentioned hereinabove, whereby a substantially smoother operation of the device and a sealing engagement of the ends of the vanes abutting against the inner surface of the rotary casing may be obtained. This is accomplished according to the invention by providing the vanes only at their outer ends with friction pins having sealing engagement with the inner peripheral wall of the rotary casing whilst the inner ends of the vanes are supported by centering surfaces open to seepage oil chambers provided between the rotary casing and vane drum. If a discharge of the seepage oil collecting in said chambers during the operation of the device is prevented, the pressure exerted by the seepage oil is utilized to hold the outer ends of the vanes or of the pins inserted therein permanently in sealing engagement with the rotary casing. The pressure caused by the seepage oil may rise up to one half of the pressure of operation when the chambers are perfectly sealed.

A further object of the invention is to form the inner end faces of the vanes in such a manner as to remove the small radial slack of the vanes which occurs on account of the eccentricity between vane drum and rotary casing. Thereby the vanes are maintained even in the inoperative condition of the engine in sealing engagement with the circumference and the centering surfaces of the rotary casing.

The invention is illustrated diagrammatically and by way of example on the accompanying drawings on which Fig. l is a longitudinal sectional view of the driving section of an infinitely variable hydraulic transmission according to the invention, the driven section being omitted as being of same construction.

Fig. 2 is a sectional view of a detail of a hydraulic transmission according to the invention illustrating a complete closure of the seepage oil chambers by a rigid disc, and

2,791,184 liiatented May :7, 1857 w 1 CE Fig. 3 shows on an enlarged scale and in fdiagrammatic form 'th'e wanes of Fig. 1 an'dthe amanner in which lthey arenupportedin'ternally.

Referring now "in *detail -'to the rlrawin-gs the vane 1 or piston drum 1 is shown to have a bearing in -form of a substantiallycylindrical hub' portion Zsupported on two ball bearings 3, 3 in a 'hoiIsing S. l lre-"ou-ter en'd of the vane drum hub 2 is pinnetl to "a driving shaft journal "6. The wane nil-um :is rotatably mounted iupon one of the j'ournals of a diffuser a ile E8 :providi'nga'connection between fthe two itransmision .sect-ions tthrou-gh inlet andoutlet channels-.or ducts. The working ilramber 10 subdivided by'the vanes 91is1enclosediina notary easing-comprising an @annular member 11 :having movers 1-2, l 2 screwedtthereon'zat :bothzs'idesssoitlrat :the working :cirarnber 31 0 :has a sicltler-sh'apetl crossssection as1.sh'own in v Fig. J 2 fof rmy ;;Batent No. ;-2,049092, fmentione'd'hereinabove, and in $.12 imentioned ihereinafter. ;%Each :of these :covers' is stormed with ra Zhub zportion 71-3 and 13 rrrespectively servingto :tsupport ball bearings 21:4, '14 'mounte'd imtlre*srotary-zcasing :carrierilS, thisilatteri'being tcapa'blezofaany desire'd'e'ccentric-adjustrnent in ithefhlousillg 5. Reference:iszmadeitoithe ll. Patents --2=,-049 ,092:and 2,750,895 .wherein'zmeans'cfor :the eccentric adjustment sofitheirotarytcasing :15 rrelative Ito the piston s'drumt- 1 care :de'scribed zin-idetail. .As will ":be -'seeI1,'.:an zannular cchambers1i6 and i1 5 respectively is :formed :between ith :hfib'rportionsrlnnd. 13, :13 .respectivelytof the wane :drum and :of 'ithe rotary :casing "respectively. These aannular chambers are closed laterally by means of rigid or resilient closing means shaped as annular discs such as spring washers 17, 17 abutting on the one hand against the hub portions 13, 13' of the rotary' casing and on the other against spring rings 18, 18' secured to the hub portion 2 of the vane drum 1. The ball bearings 3, 3' have interference fit with the hub portion 2 of the vane drum 1 adjacent the spring rings 18, 18'. A cover 4 serves to close the axial opening of the housing 5.

As will be seen in the lower half of Fig. l, the two chambers 16, 16' are in communication with the chamber 19 behind the vane 9. In all of these chambers the seepage oil from the working chamber 10 between the vane guides is collected. Since this seepage oil is prevented from escaping by the spring rings 18, 18, the oil pressure within the seepage oil chambers 16, 16' holds the vanes 9 in engagement with the inner peripheral wall of the rotary housing. Only when this pressure is rising above a predetermined admissible limit, oil is permitted to escape past the somewhat yielding spring rings 18, 18 into the oil sump in the housing 5. Seepage oil passing between the diffuser axle 8 and its mounting and collecting in the chamber or gap 20 between journal 7 and driving shaft journal 6 is permitted to flow out without pressure through the outlet or bores 21 into the oil sump and separately from the leakage oil flowing to the seepage oil chambers. 7

As best shown in Fig. 2, the lateral closure of the seepage oil chambers may be obtained by a rigid annular disc 27 instead of by a resilient ring 17 as described above in connection with Fig. 1, so that the vanes are urged against the inner surface of the rotary casing by means of the oil pressure increasing during the operation of the device.

In order to obtain an increased quietness of the engine,- in particular when starting, it is important that with the rotary casing being eccentrically adjusted all of the vanes have engagement with the annular member 11 even in the inoperative condition of the engine. This is accomplished in the case of a hydraulic engine according to the invention by shaping the vanes, while being of maximum length, at their inner ends according to a circular arc with the radius r from the center of the rolling pin 9', as shownin Fig. 3. This has as a consequence that comprising in combination: a central journal having inlet and outlet channels for the liquid fluid, a piston drum rotatable about said journal and having alternating radial slots and radial channels, vanes shiftable in said radial slots, an eccentn'cally adjustable rotatable casing enclosing said piston drum and forming with the piston drum a sickle-shaped working chamber subdivided by said vanes and communicating by said radial channels with the inlet and outlet channels of said central journal, a plurality of chambers arranged between the hub portions of said rotatable casing and the hub portion of said piston drum, said chambers being connected with one another by said radial slots housing said vanes, and being adapted to be filled with seepage-oil during operation of the engine,

' closing means laterally closing said chambers and holding the same under seepage-oil pressure, which acts upon the inner end faces of said vanes, crescent-shaped friction pins arranged, respectively, between the outer ends of said vanes and the inner wall of said rotatable casing, each of said pins being rotatable about a longitudinal axis thereof and in close contact with the circular inner wall of said rotatable casing, and a supporting surface for the inner ends of said vanes, said supporting surface A with an eccentric position of the rotary casing the, vanes being arranged concentrically with said inner wall of said rotatable casing.

2. A rotary piston engine as claimed in claim 1, said inner end faces of said vanes adjacent to said seepage-oil chambers having a circular contour centered on the center of said friction pins and being adapted to maintain said pins in contact with the inner surface of the rotary casing when the piston drum is stationary.

3. A rotary piston engine as claimed in claim 1, said laterally closing means for said seepage-oil chambers comprising resilient annular discs being under axial pressure.

References Cited in the file of this patent UNITED STATES PATENTS 582,696 Schneible et al. May 18, 1897 1,626,557 Rolatf Apr. 26, 1927 1,635,523 Wilson July 12, 1927 1,927,395 Edwards Sept. 19, 1933 2,002,827 Morch May 28, 1935 2,049,092 Sturm July 28, 1936 2,102,344 Wishart Dec. 14, 1937 2,233,551 Ott Mar. 4, 1941 2,678,607 Hufierd et al May 18, 1954 2,685,842 Hufferd Aug. 10, 1954 FOREIGN PATENTS 489,760 Germany Jan. 22, 1930 596,902 Great Britain Jan. 13, 1948 France Jan. 2, 1940 OTHER REFERENCES Ser. No. 239,352, Sturm (A. P. 0 published May 11, 1943. 

